Airbus rudder AD

George Patterson wrote:

jsmith wrote:

The "tap test", as used on fiberglass homebuilts, is used to detect
voids (air bubbles) in the epoxy/glass matrix. One usually uses a
Quarter to gently tap the surface. If there are any voids, the
difference in sound will be noticeable.


How long do you think it will take to do this on an Airbus rudder?

George Patterson
I prefer Heaven for climate but Hell for company.


Use a Half Dollar then... and pack a lunch..

Dave

("C J Campbell" wrote)
A tap test? Is this is the best they can do to find possible flaws on
multimillion dollar aircraft, carrying thousands of people around?

What is that? They whack it with a hammer to see if it breaks? What about
cracks and damage caused by the test?


I read that composites don't show cracks, instead they have weak 'air
pocket' spots that can't be seen during inspections. These pockets of air
bubles(?) are caused by heat/cold to the composite structures over time.

Think early British Comet jets - we're learning as we go I guess.

Whack, whack, whack ...she's good to go.


Montblack - sorry no link

In a previous article, "Montblack" said:
I read that composites don't show cracks, instead they have weak 'air
pocket' spots that can't be seen during inspections. These pockets of air
bubles(?) are caused by heat/cold to the composite structures over time.

My father, who was the Chief of Non-Metallic Materials at deHavilland
Canada said that this is bunk. Once the composite is made and given the
initial inspection, there is no way in hell they could delaminate like
that.


--
Paul Tomblin http://xcski.com/blogs/pt/
We're the technical experts. We were hired so that management could
ignore our recommendations and tell us how to do our jobs.
-- Mike Andrews

Morgans wrote:
"Matt Whiting" wrote


True, but we don't have 50 years of experience with composites in
service. Who knows what their deterioration/age related failure modes
may be? Remember, it took a couple of fatal accidents to begin to
understand fatigue and corrosion issues in aluminum...


Matt


My outrage is not whether the composites have a problem, but the method with
which they are to determine if there is a problem.

With some question (there must be a concern, hence an AD) there HAS to be a
better way than a tap test. It does nothing for my confidence.

Sometimes the simple tests really are the best. Visual inspection by
human eyes is still used for a lot of things even though it is well
known to have lots of problems (variability among humans being one of
the biggest).

Matt

Montblack - you said exactly what I was thinking - British Comets.

Dave
68 7ECA


Montblack wrote:
("C J Campbell" wrote)

A tap test? Is this is the best they can do to find possible flaws on
multimillion dollar aircraft, carrying thousands of people around?


What is that? They whack it with a hammer to see if it breaks? What about
cracks and damage caused by the test?



I read that composites don't show cracks, instead they have weak 'air
pocket' spots that can't be seen during inspections. These pockets of
air bubles(?) are caused by heat/cold to the composite structures over
time.

Think early British Comet jets - we're learning as we go I guess.

Whack, whack, whack ...she's good to go.


Montblack - sorry no link

True, but we don't have 50 years of experience with composites in
service. Who knows what their deterioration/age related failure modes
may be? Remember, it took a couple of fatal accidents to begin to
understand fatigue and corrosion issues in aluminum...


Matt

Composite materials are pretty well understood by now. The Airbus
problems are not going to be found to be inherent in the materials, but
ones of design and quality control.

My fiberglass glider (Glasflugel H301) has been in service for 41 years.
It has not even been refinished. Most people think it is nearly new when
they see it. The fiberglass has not delaminated anywhere on it, Although
the gelcoat is clearly deteriorating and it will need refinishing soon.
The bird flies regularly. I usually put at least 100 hours/year on it,
more if the weather permits. I flew it over 200 miles this past weekend.
It gets pretty rough treatment compared to most planes. Landing in rough
fields, continuous hard pullups into thermals, often making 2 g turns to
center tight thermal cores, extreme turbulence while mountain flying,
etc. Those wings have flexed through a lot of cycles. That model has
only about 8 AD's (in the US) on it. All concern the metal parts.

Lest you think I'm a 'glass chauvinist, I also have a rag, tube, and
stick airplane (Stits SA-6), and a half share of a 1958 Cessna 175.

--
Take out the airplane for reply

("Wallace Berry" wrote)
snip
My fiberglass glider (Glasflugel H301) has been in service for 41 years.
It has not even been refinished. Most people think it is nearly new when
they see it. The fiberglass has not delaminated anywhere on it, Although
the gelcoat is clearly deteriorating and it will need refinishing soon.
The bird flies regularly. I usually put at least 100 hours/year on it,
more if the weather permits. I flew it over 200 miles this past weekend.
It gets pretty rough treatment compared to most planes. Landing in rough
fields, continuous hard pullups into thermals, often making 2 g turns to
center tight thermal cores, extreme turbulence while mountain flying,
etc. Those wings have flexed through a lot of cycles. That model has
only about 8 AD's (in the US) on it. All concern the metal parts.


I wonder if OAT is a common denominator missing here?

I thought it was (FL350) cold cycles they were looking at?


Montblack

"Matt Whiting" wrote in message ...
Sometimes the simple tests really are the best. Visual inspection by human eyes is still used for a lot of things
even though it is well known to have lots of problems (variability among humans being one of the biggest).

Matt

But once someone knows what they are looking for it is very hard to beat...

On Thu, 24 Mar 2005 01:07:28 GMT, "Blueskies"
wrote:


"Matt Whiting" wrote in message ...
Sometimes the simple tests really are the best. Visual inspection by human eyes is still used for a lot of things
even though it is well known to have lots of problems (variability among humans being one of the biggest).

Matt

But once someone knows what they are looking for it is very hard to beat...

Way back in my aerospace days, the guy at the next desk had a casting
he used as an ashtray. (I said this was way back.) The casting had a
tiny crack, and right across the middle of the crack was the QC
inspector's stamp.

Don

"Don Tuite" wrote in message ...
Way back in my aerospace days, the guy at the next desk had a casting
he used as an ashtray. (I said this was way back.) The casting had a
tiny crack, and right across the middle of the crack was the QC
inspector's stamp.

Don

Which begs the question...were they certifying the crack or were they certifying the part?